This invention relates to an apparatus for installing a disk, and more particularly to an apparatus for detachably installing a disk rotatively driven by a motor to a disk holder.
Recent information processing systems including, for example, an optical disk memory have various merits such a recording density several ten to hundred times greater than that of a magnetic memory; capability of making high speed random access to; excellent long-period stock property; a ready recording system; capability of additional recording and inexpensive cost per bit. Thus, this kind of optical information processing system finds extensive applications as recording/reproducing system or as exclusive reproducing system. The exclusive reproducing type optical information processing system finds applications in home video disks, business video disks, audio PCM disks, etc. The recording/reproducing type optical information processing system finds applications in document files, video files, general computer memories, etc.
Heretofore, in an optical information processing system like this, the apparatus for installing a disk to be rotatively driven comprises a disk support (turntable) fixed to a driving shaft and supporting the disk at the center of its one side and a pressure member which is screwed on the thread provided on the distal end of the driving shaft and presses down on the disk at the center of its other side. The driving shaft is fitted into the through hole which is formed in the center of the disk for the disk positioning purpose, thereby to restrict the radial movement of the disk. The movement of the disk in the longitudinal direction of the driving shaft is restricted by holding the disk between the disk holder and the disk pressure member. However, in order to install or remove the disk, it is necessary for the pressure member to screwed onto the driving shaft or to be loosened. This operation is very troublesome. Moreover, the tightness tends to vary according to the operator using this particular apparatus. Accordingly, the excessive tightness would result in the deformation of the disk or insufficient tightness would cause the disk to become loosened during operation. As stated above, the disk installing apparatus previously in use often exerted adverse effects upon the information processing operation.